The present invention relates to a system for inserting reagent or macrobeads into one or more bores of a sample plate and a method of inserting reagent or macrobeads into one or more bores of a sample plate.
A technology has been developed which enables multiple tests to be carried out in a single well of a sample plate. The technology uses macro sized (e.g. mm sized) reagent beads that are coated with specific antigens or antibodies. Each well of a sample plate comprises multiple bores in the base portion of the sample plate. Reagent or macro beads are pressed and retained in the bores of each well by an interference fit so that the top half of bead is within the well and is exposed to the assay test.
U.S. Pat. No. 6,074,609 discloses a system for arraying microbeads. The microbeads disclosed in U.S. Pat. No. 6,074,609 are of the order of 5-300 μm i.e. are an order of magnitude smaller than the macrobeads used according to a preferred embodiment of the present invention. The microbeads are stored in a reservoir holding a liquid medium. A distal end of a transfer member is lowered into the liquid medium and a vacuum is created within a lumen to draw a microbead onto the distal end of the transfer member. The transfer member is then lifted from the reservoir whilst holding the microbead on the distal end. The transfer member is then positioned in a test well holding another liquid medium. The vacuum is then removed and the microbead is released from the transfer member whilst the transfer member is within the liquid medium. The microbead is then allowed to fall under the force of gravity within the liquid medium.
There are a number of problems with the arrangement disclosed in U.S. Pat. No. 6,074,609.
One problem with the arrangement disclosed in U.S. Pat. No. 6,074,609 is that as a microbead is being drawn towards the distal end of the transfer member the lumen will at least partially fill with fluid. This can cause a serious problem with cross-contamination.
Another problem with the arrangement disclosed in U.S. Pat. No. 6,074,609 is that the microbeads and in particular any sensitive coating on the microbeads may become damaged whilst the microbead is being transferred by the transfer member.
It is desired to mass produce sample plates and to improve the process of locating reagent or macrobeads in the bores of a sample plate.